Copolymer of acrylonitrile and a quaternary imidazolium compound, method of making same, and a spinning solution thereof



United States Patent COPOLYMER OF ACRYLONITRILE A QUA- TERNARY IMIDAZOL'IUM COMPOUND, METH- OD OF MAKING SAME, AND A SPINNING SOLU- TION THEREOF John A. Price, Stamford, 'Conn, assignor to American 'Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Application August 30, 1954 Serial No. 453,162

Claims. 01. 260--29.6)

More particularly the present inventionis directed to a i new class of quaternary imidazolium braced by the general formula compounds emwherein R represents a radical of the class consisting of alkyl, hydroxyalkyl (monohydroxyalkyl) and .aralkyl radicals, and Y- represents an anion; and to homopolymers and copolymers of quaternary imidazolium compounds of the aforementioned class. My invention also embraces polymerizable compositions comprising (1 a compound of the class covered by Formula I and :-(2). a compound which is different from the compound of (1), which is copolymerizable therewith and which contains CH =C grouping; as well as products comprising the polymerized, composition just described.

Illustrative examples of alkyl radicals represented. by

fide, cyanate, acetate and the other common inorganic and organic anions.

More specific examples of quaternary imidazolium compounds embraced by Formula I are salts represented by the formulas substance which is copolymerizable therewith: The

i an anion, numerous examplesof which have been 10 IV N 1210/ 011 nii-1Lr-on=on, -Y

nr ornon wherein, in each of the above formulas, Y- represents given hereinbefore. Other examples include:

N-benzyl-N-vinylimidazolium chloride N-rnethyl-N-vinylimidazolium bromide N-beta-hydroxyethyl-N-vinylimidazolium phosphate N-isopropyl-N-vinylimidazolium sulfate .N-phenylethyl-N-vinylimidazolium sulfonate N-3-hydroxypropyl-N-vinylimidazolium bromide N-hexyl-N-vinylimidazolium thiocyanate N-dodecyl-N-vinylirnidazolium phosphate Other examples will be apparent to those skilled in the art from Formula I and from the illustrative examples hereinbefore given of radicals represented by R and of anions represented byY-.

It is an object of the present invention to provide a new class of quaternary imidazolium compounds, more particularly a new class of unsaturated quaternary itnidazolium compounds of the kind embraced by Formula Lfand polymerization products thereof.

Another object of the present invention is to provide a new class of polymerizable compositions containing (1) a compound of the kind embraced by Formula I (or a plurality of such compounds) and (2) one or more other comonomers copolyrnerizable therewith, and anew class of copolymercompositions' from the said polymerizable compositions.

Another object of the invention is to provide a new class of synthetic compositions, more particularly polymerization products, which are especially suitable for use in the plastics, coating, adhesive, laminating, molding, fiber-forming and other arts.

Another object of the invention is the production of new copolymers, more particularly new aerylonitrile copolymer compositions, which are more readily dyed, especially with acid dyes, than homopolymeric acrylonitrile or many of the copolymers of acrylonitrile and another monomer or monomers that were known or suggested prior to my invention.

Another object of the invention is to prepare such acrylonitrile copolymers which can be spun or otherwise shaped to form filaments, tapes, ribbons, tubes, rods,

sheets, etc., and the shaped articles then dyed either before or after having been oriented or treated to improve whichfol-low.

These objects are accomplished, in general, by preparing a quaternary imidazolium compound of the kind embraced by Formula I and then polymerizing this compound alone or, preferably, while admixed with another polymerization product advantageously is preparedby polymerizing the polymerizable substance including the aforementioned unsaturated quaternary imi'dazoliumcompound in an aqueous medium with the aidof a polymerization catalyst, and recovering the resulting polymeri'c product by anysuitable means, eig., by filtration,

centrifuging, etc.

Any suitable method can be used in preparing-the quaternary imidazolium compounds embraced by Foimula I and which are used in producing the hoinopoly- -rneric and copolymeric compositions. They Empi e? H Ho----N--orr=on,

Any suitable quaternizing agent can be used in preparing the quaternary pyridinium compound from the aforementioned intermediate. Examples of such quaternizing agents are the alkyl and aralykyl halides (e.g., methyl, ethyl, butyl, octyl, decyl, lauryl, octadecyl, benzyl, phenylethyl, etc., chlorides, bromides, etc.), alkyl sulfates such as the dimethyl diethyl, dipropyl, di-isopropyl, dibutyl, diisobutyl, dioctyl, dilauryl, etc., sulfates, alkyl aryl sulfonates such as butyl benzene sulfonate, butyl toluene sulfonate, ethyl toluene sulfonate, octyl benzene sulfonate, etc.

A general procedure for the preparation of the quater nary imidazolium compounds of the present invention, and which is given for purpose of illustration only, is as follows: Approximately equivalent amounts of, for 'example, the appropriate halide, specifically the chloride or bromide, and N-Vinylimidazo'le are mixed in areaction vessel together with an equal volume of an inert diluent or reaction medium, e.g., benzene. The reaction temperature varies in specific cases between, for example,

25 C. and 100 C. The time of reaction also varies in specific cases from, for instance, 0.5 to 24 hoursy 'I 'he precipitated quaternary imidazolium compound is then isolated, as by filtration through a Biichner funnel, ,washed thoroughly with fresh benzene or other suitable solvent for any unreacted material, and dried, for instance it under a vacuum in a desiccator.

The free quaternary imidazolium base can be prepared from any of the hereindescribed quaternary irnidazolium .salts of inorganic acids by treating a water-free solution of the salt, for instance the chloride, in n-butanol (or isopropanol or tert;-butanol) with a slight excess of the sodium salt of the alcohol used. After cooling and standing for about 16 hours, the crystalline sodium salt .of the inorganic acid is filtered from the solution of quaternary imidazolium alkoxide. Water is added to the e mixture to yield the quaternary imidazoliumhydroxide.

Any suitable means may be used in effecting polymerization of the quaternary-compound alone or admixed with one or more other substances which are cm -polymerizable therewith. Heat, light, or both heat and light, with or without a polymerization catalyst can be used. A polymerization catalyst preferably is employed in order to shorten the period of time required for polymerization- I Any of the polymerization catalysts which are suitable for use in polymerizing compounds containing an ethylenically unsaturated grouping, specifically a vinyl grouping, can be employed. Among such catalysts are the various organic peroxy catalysts, illustrative examples of which latter are: the dialkyl peroxides, e.g., diethyl peroxide, dipropyl peroxide, dibutyl peroxide, dilauryl .peroxide, dioleyl peroxide, distearyl peroxide, di-(tert.- butyl) peroxide and di-(tert.-amyl) peroxide; the alkyl .hydrogen peroxides, e.g., tert.-bu tyl hydrogen peroxide (tert.-butyl hydroperoxide), tert.-amyl hydrogen peroxide q (tert.-amyl hydroperoxide), etc.; symmetrical diacyl peroxides, for-instance peroxides which commonly are known under such names as acetyl peroxide, propionyl peroxide, .lauroyl peroxide, stearoyl peroxide, malonyl peroxide,

.succinyl peroxide, phthaloyl peroxide, benzoyl peroxide,

..etc.; fatty oil acid peroxides, e.g., coconut oil acid peroxides, etc.; unsymmetrical or mixed diacyl. peroxides, e.g., acetyl benzoyl peroxide, propionyl benzoyl peroxide, -etc.; terpene oxides, e.g., ascaridole, etc.; and salts of inorganic per-compounds, examples of which are given .hereinafter. Other so-called free radical types of cat- .alysts, e.g.,- ,a'azodiisobutyronitrile, also can be used 4 to accelerate polymerization. The various known redox (reduction-oxidation) catalyst systems also can be employed, and are especially adapted for use when the polymerizable substance (monomer alone or admixed 5 with another polymerizable substance) is polymerized in an aqueous medium. Such water-soluble catalyst systems generally I comprise a water-soluble catalyst or catalysts "and a'water-soluble activator. Illustrative examples of water-soluble catalysts are water-soluble, oxygen-yielding 1O peroxy compounds, e.g., the water-soluble peroxides, peracids and persalts, including hydrogen peroxide, organic peroxides, e.g., diacetyl peroxide, urea peroxide, 'etc., peracetic acid, the various water-soluble perchlorates, persulfates, percarbonates, pen-borates, perphosphates, etc,.

e.g., the ammonium and alkali-metal (sodium, potassium, lithium, etc.) salts of percarbonic, peracetic, perboric, perphosphoric,persulfuric,--perchloric, etc., acids; watersoluble chlorates, e.g., ammonium, sodium and potassium chlorates, etc.; water-soluble ferric salts capable of yieldmg ferric ions, including the various ferric alums, e.g., ferric ammonium sulfate (ferric ammonium alum), ferric sodium sulfate, ferric potassium sulfate, etc. Other examples of water-soluble additives comprising a watersoluble catalyst that may be used in producing the polymers (homopolymers and copolymers) of the present invvention are given in, for instance, US. Patents 2,289,540,

2,380,474, --5, 6, --7, 2,380,617, 8, 2,380,710, 2,383,425, 2,384,544, 2,384,571, 2,384,574, 2,388,373 and 2,395,017.

Illustrative examples of water-soluble activators (watersoluble polymerization adjuvants) of the catalyst are oxygen-containing sulfur compounds which are capable of undergoing oxidation, for instance sulfur dioxide, the alkali-metal (e.g., sodium, potassium, etc.) bisulfites, hydrosulfites, thiosulfates, sulfurous acid (or compounds which engender sulfurous acid, e.g., alkali-metal sulfites,

ethyl and other alkyl sulfites, etc.), various organic sulfinic acids, e.g., p-toluene sulfinic acid, formamidine sulfinic acid, etc. If alkali-metal sulfites, e.g., sodium sulfite,

40 or similar compounds which engender sulfurous acid are used, the aqueous solution also should contain a strong acid, e.g., sulfuric acid, etc., in an amount which is at least chemically equivalent to the amount of such a compound engendering sulfurous acid that is employed.

If desired, the polymerizable substance can be poly- -merized in emulsion or in solution state to yield a poly- -mer. Good results are obtained by effecting polymerization while the polymerizable material is dissolved in a suitable solvent, preferably water or a liquid solvent comprising mainly water. Suitable inert organic solvents can be used if desired, e.g., benzene, toluene, xylene, .etc. Preferably the polymerization reaction is carried out in a liquid medium in which the polymerizable substance is soluble but the polymer is insoluble. e.g., water.

, The polymerization also can be effected by conventional 'bulk polymerization technique, in the presence or absence of a solvent capable of dissolving the polymerizable material and in which the latter preferably is inert; 0 or by conventional bead polymerization methods. The

polymerization of the polymerizable substance can be .effected by a continuous process as well as by a batch operation.

The concentration of the catalyst is relatively small, 5 e.g., from, by Weight, about 1 part of catalyst per 1,000 parts of the polymerizable material to about 4 or 5 parts of catalyst per 100 parts of the said material. The amount of polymerization adjuvant or activator used likewise maybe varied considerably, but generally is within the range of from about 0.1 to 1 molar proportion based on the catalyst used or an amount which is chemically equivalent to the amount of catalyst employed. The use of higher ratios of activator with respect to the catalyst is not precluded, e.g., 2 er 3 or more moles of activator per mole of catalyst, or correspondingly larger tion temperature will be "or C., preferably at least to-" 0, up to the boiling temperature of the polymerizable material, depending, for example, upon theparticular catalyst, if any, used, the rapidity of polymerization wanted and other .cially with acid dyes.

"proportions on a a ciiemicar equivalent basis, but no -=particular advantages ordinarily accrue therefrom.

Forms of radiation other than ultraviolet or visible light may also 'beused to initiate polymerization. Ex-

merizable substance or indirectly (ifa solvent or other substance is present) by the action of radicals resulting from irradiation of these substances. 1

The polymerization reaction may be effected, if desired, while the aqueous mediumds. maintained under an atmos- :phere of aninert gas, for example nitrogen, helium, carbon dioxide, etc.; or, it may be (but preferably is not) carried out under an atmosphere .of air.

The temperature at which the polymerizable material is polymerized can be varied over a wide range, up to and including or slightly above the boiling .point (at' atmospheric pressure) of :the monomer or mixture of polymerizable substances. In most cases, the polymerizawithin'the range of about 20 influencingfactors. The use of polymerization temperatures substantially above the boiling point of the mono- W mer or mixture of polymerizable substances is not precluded, but generally is less desirable because the polymerization reaction then must either be carried out in a closed reaction vesselunderpressure, or, for economical reasons, with a reflux condenser or other means provided v for the recovery and re-use of the volatilized monomer or monomers if the reaction is carried out at the boiling temperature of the mass unter atmospheric pressure.

The polymers of this invention can be produced in various molecular weights as desired or'as conditions may require. Thus, the fiber-forming (fiber-formable) copolymers, more particularly the fiber-forming acrylonitrile copolymers, ordinarily are within the range of about 15,000 to about 300,000-or higher as calculated from viscosity measurements using the Staudinger equation (reference: US. Patent No. 2,404,713). Homogeneous acrylonitrile copolymers having an average molecular weight of between about 60,000 and 90,000 and which contain at least 70%, advantageously from about 80% to about 95% of acrylonitrile (combined acrylonitrile) I in the molecule, are especially suitable for use inmaking dyeable, oriented fibers by wetordry-spinning methods.

If the polymerization reaction is carried out while thepolymerizable material is dissolved or dispersed in a liquid medium, e.g., in solution in water, the resulting polymerthen is separated from the said medium by any suitable means, e.g., by filtration, extraction, etc.

The quaternary imidazolium compound may be used centrifuging, solvent alone in various detergent, germicidal, fungicidal, antistatic, plastics, and other applications. The homopolymer is also useful in many applications, e.g., as a modifier of a polymer of acrylonitrile to improveits dyeability, espe- Or, in order to modify'the properties of the quaternary imidazolium compound and to widen the field of utility, it can be fcopolymerized with other -substances which are different therefrom and copolymerizable therewith, etgi, compounds containing 'a CH =C groupingvand which "are different from the quaternary compound, unsaturated alkyd resins, mixtures of individual members of either or both of these classes of polymerizable unsaturated materials, as well as other copolymen'zable substances.

.,Illustrative examples of substances that can be co polymerized with a quaternary imidazolium compound of the hind embraced by Formula I arevinylcompounds, \including the vinyl and isopropenylaromatic compounds, more particularly thevinyl-andisopropenyl aromatic hydrocarbons (e.g., styrene, isopropenyl toluene, the various dialkyl styrenes, etc.), other aliphatic compounds containing a CH =C grouping, e.g., acrylonitrile and the various substituted'acrylonitriles (e.g., methacrylonitrile, ethacrylonitrile, 'phenylacrylonitrile, etc), the various acrylamides (e.g., acrylamide itself, "methacrylamide, ethacrylamide, the N-nionoalkyl and -dialkyl acrylamides and methacrylamides,e.g., N-monomethyl, -ethyl, -propyl, -buty1, etc., andN-dirnethyl, -ethyl, -propyl, butyl, etc., acrylamides and methacrylamides, N-monoaryl and -diaryl acrylamides and alkacrylamides,e;g., N-monophenyl and -diphenyl acrylamides and methacrylamides, the various N-B-hydroxyethyl acrylamides, etc.), vinyl esters, e.g., vinyl acetate, vinyl 'propionate, vinyl butyrate, vinyl isobntyrate, vinyl valerate, vinyl acrylate,vinyl methacrylate, etc., esters of an acrylic acid (including acrylic acid itself and the various alpha-substituted acrylic acids, e.g., methacryic acid, ethacrylic acid, phenylacrylic acid, etc.), more particularly the alkyl esters of an acrylic acid, e.g., .the ethyl, propyl, isopropyl, n-butyl, isobutyl, sec.-butyl, tert.-butyl, amyl hexyl, heptyl, octyl, decyl, dodecyl, etc., esters of acrylic, methacrylic, ethacrylic, phenylacrylic, etc., acids including the alkl acrylates containing not more than four carbon atoms in the alkyl grouping, examples of which are given above, as well as other vinyl aromatic and vinyl aliphatic compounds, and other compounds containinga CH =C grouping, more, particularly a single "CH =C grouping.

Other examples of copolymerizable.substandes thatcan be employed alone .or in conjunction with one .or more compounds containing a CH =C grouping include the polymerizable unsaturated alkyd resins (modified or unmodified), e.g., ethylene glycol maleate, diethylene glycol maleatephthalate, ethylene glycol maleate succinate and diethylene glycol maleate linoleate. Other and more specific examples of unsaturated alkyd resins that can be used are given, for example, in Nyquist and Kropa Patent No. 2,503,209, dated April 4, 1950, and patents referred to therein (see, for instance, column 8, lines 1-64).

Still other examples of materials that can-be copolymerized with the quaternaryimidazolium compound of the kind embraced by Formula I are given in Kropa 'Patent No. 2,510,503 e.g., column 2,'line 46, to the end of the sentence in line 16, column 3; column. 5,line 54, through line 46, column 7; and column 13, line 42, through line 30, column 16); and in the aforesaid Nyquist et a1. Patent No. 2,503,209 (see, forinstance, column 5, line 67, through line 75, column 7; and column 9, line 74, through line 12, column 11).

The'proportions of the quaternary imidazolium compound andunsaturated material which is copolymerizable therewith may be widely varieddepending, for instance, upon the particular starting materials employed and the particular properties desired in the copolymer, e.g., in weight ratios of from 1:99 to 99:1, and more particularly from 5:95 to :5. Mainly for economical reasons, it is usually desirable that the quaternary imidazolium compound does not exceed about 50% by weight of the total monomers. For example, I may use advantageously from about 2% to about 40% of the quaternary imida zolium compound and from about 60% to about 98% of the other copolymerizable substance or substances, e.g., a dilferent vinyl compound or compounds, and. morespecifically acrylonitrile, in producing. new and valuable copolymer compositions. The percentages just mentioned 0 are by weight.

.t'ernary imidazoliurn compound of the kind embracedby .Formula I can be varied as desired or as conditions may require. Ordinarily, however, the acrylonitrile constitutes a major or preponderant proportion (more than 50%) by weightof the total weight of monomers to be copolymerized, the quaternary imidazolium compound constituted from about 1 or 2% to about 15 or 20%, or

in some cases as high as 25 or 30%, ofthe total weight of the acrylonitrile and quaternary imidazolium compounds, and any modifying comonomer or comonomers I (if present in the polymerizable mixture) constitute the addition salts of N-vinylirnidazole are unstable and liberate the free base, with obvious advantages in the commercial utilization of the compounds. A further and very important advantage flowing from the quaternary imidazolium compounds of this invention resides in the fact that they form copolymers with certain monomers, particularly acrylonitrile, which are much more readily and more efiectively dyed, especially with acid dyes, than similar copolymers wherein, for example, an equivalent amount of N-vinylimidazole has been substituted for the quaternary derivative thereof. The difference is one of kind and not merely of degree; in other words, N-vinylimidazole and quaternarized N-vinylimidazole are nonequivalents in forming polymerization products thereof, especially in forming copolymers with acrylonitrile.

In order that those skilled in the art may better understand how the present invention can be carried into effect, the following examples are given by way of illustration and not by way of limitation. All parts and percentages are by weight.

, EXAMPLEl Preparation of N-benzyl-N-vinylimidazolium bromide To a reaction vessel are charged .4 part of N-vinylimidazole and 34.2 parts of benzyl bromide. The solution is allowed to stand for 30 minutes. During this period an exothermic reaction takes place. The reaction product is washed twice with 25 parts of benzene and dried in a desiccator to constant weight. The yield of white, crystalline N-benzyl-N-vinylimidazolium bromide amounts to 24.8 parts.

EXAMPLE 2 Preparation of N-vinyl-N-(Z-hydroxyethyl)imidazolium sulfate To a reaction Vessel equipped with stirrer, thermometer, Dry Ice-acetone reflux condenser and gas-inlet tube are added 94 parts of N-vinylimidazole, 39.1 parts of sulfuric acid, 114 parts of water and 40 parts of isopropanol.

The vessel'is placed on a steam bath. Over a period of 100 minutes, 43 partsof ethylene oxide (98% of the theoretical) is bubbled into the vessel beneath the surface of the solution at a temperature of 6479 C. The

rate of addition is controlled by the amount of ethylene oxide that is refluxing. The addition of ethylene oxide is stopped and the solution is stirred for an additional hour at the same temperature. No refluxing of ethylene oxide is evident at the end of this period. The solution of N-vinyhN-(Z-hydroxyethyl) imidazolium sulfate is then completely neutralized by the addition of sulfuric acid.

EXAMPLE 3 "Preparation of N-methyl-N-vinylimidazolium methylsulfate a reaction vessel'containing 18.8 parts of N-vinylvirnidazole is slowly added, with cooling, 25.2 parts of di methyl sulfate. The resulting solution is heated on a steam bath for four hours. It is then washed three times .with 50 parts of benzene. The tan-colored crystalline product is collected on a Biichner funnel and dried in .a vacuum desiccator to a constant weight. Thirty-five (35) parts of N-rriethyl-N-vinylimidazolium methylsulfate is obtained. a

' 7 EXAMPLE 4 This example illustrates the preparation of a homopolymer of N-benzyl-N-vinylimidazolium chloride from a polymer of N-vinylimidazole. i To areaction vessel are added 10 parts of N-vinyl- 'imidazole and 0.2part of alpha,alpha'-azodiisobutyronitrile. The solution is heated on a steam bath for '2 hours. An additional 0.1 part of alpha,alpha-azodiisobutyronitrile is added, and heating is continued for another 2 hours. The resulting polymer is dissolved in 40 parts of benzene, re-precipitated in 250 parts of ethanol and dried in an oven at 70 C. for 4 hours. 'The yield of dry, cream-colored polymer of N-vinylimidazole amounts to 7 parts. p

A portion of, this polymer (2.5,parts) is dissolved in 20 parts of benzene, treated with 10 parts of benzyl chloride and allowed to stand at room temperature for-3' days. The precipitated product is collected on a Biichner funnel, washed with parts of benzene and dried to a .constant weight in a vacuum desiccator. A good yield of tan-colored, water-soluble, homopolymeric N-benzyl- N-vinylimidazoliurn chloride is obtained.

EXAMPLE 5 To a reaction vessel are added 2.5 parts of homopolymeric N-vinylimidazole (prepared as described under Example 6), 20 parts of benzene and 10 parts of dimethyl sulfate. After standing for 24 hours, the product that precipitates from the clear solution is collected on a Biichner funnel, washed with 80 partsof benzene and dried in a vacuum desiccator to a constant weight. A good yield of tan-colored, water-soluble, homopolymeric N-methyl-N- vinylimidazolium methylsulfate is obtained.

EXAMPLE 6 This example illustrates the preparation of homopolymeric acrylonitrile, which islsubsequently employed in Y comparative dye tests with some of the copolymers of the present invention. i

A reaction vessel, equipped with a stirrer, reflux condenser, thermometer and gas-inlet tube, is placed in aco'nstant-ternperature bath which is maintained at 35 C. To the vessel is added a solution of 53.0 parts of acrylonitrile,

900 parts of distilled water and 0.29 part of sulfuric acid. The pH of the initial solution is 3.1. A rapid stream of pre-purified nitrogen ispassed over the surface of the solution for 30 minutes. The nitrogen flow is then reduced to about one bubble per second. A reductionoxidation catalyst system (redox system) consisting of 1.71 parts of ammonium persulfate and 0.71 part of sodium meta-bisulfite, each'dissolved in 50 parts of water, is then added. The solution first becomes cloudy at the end of 3 minutes, and the-polymerization is fairly exothermic for the first half hour. The polymerization is 'continued for a total of 4 hoursat 35 C. The polymer is collected on a Biichner funnel, and washed with 1000 parts of distilled water followed by about parts of methanol. The polymer is dried in an oven at 70 C. for about 16 hours. The yield of dry polyacrylonitrile,

which is white, amounts to 48 parts.

' EXAMPLE 7 denser,thermometer and gas-inlet tube,is placed'in a constant-temperature bath which is maintainedatB C. To the vessel is "added a solution of 50.35 parts ofacr-ylonitrile, 2.65 parts of methyl acrylate, 900 parts of distilled Waterand 0.44lpart ofsulfuric acid. A rapid stream of pm-purified nitrogen is passed over the surfaceof .the solu tion for 30 minutes. The nitrogen flow is then reduced to about one bubble per second. A reductionoxidation catalyst system (redox system) is prepared by dissolving 0.238 part of sodium chlorate and 0.843 part of sodium sulfite, both dissolved in 100 parts of water. The catalyst solution is added portion-wiseto the reaction vessel at 25-minute intervals over .a period of 2.5 hours. The-polymerization is continued-for a-total-of 4 hours at 35 C. The copolymer is collected on a Biichnerfunnel,

and-Washed with l000.parts of distilled water. The co- ,polymer is dried in an oven at 70 C. for about 3 hours to constant 'weight. The yield of dry acrylonitrile-methyl acrylate cqpolymer, which is white, amounts to -44. parts.

Thefollowing examples illustrate the preparation of various copolymers of the invention.

EXAMPLE 8 To a .reaction vessel are added 9 parts of acrylonitrile,

1 part of N -methy1-N-vinylimidazolium methylsulfate, 9.0

parts of water and 0.5 part of ammonium persulfate. The solution is warmed on a steam bath for 1 hour. The .precipitate is collected on a Biichner funnel, washed With 500 .parts of Water and dried in anoven at 70 C. for 4 hours.

.A good yield of dry, white copolymer of acrylonitrile and N-methyl-N-vinylimidazolium methylsulfate is obtained.

EXAMPLE 9 To a reaction vesselequipped as inExample 7 is added a solution of 95.4 parts of acrylonitrile, 10.6 parts ofN- vinyl-N-(Z-hydroxyethyl)imidazolium sulfate, 800 parts of 'dernineralized water and 0.60 part of sulfuric acid. 7 "The pH of the solution is 3.0. A rapidstream ofprepurified nitrogengas is passed over the surface of the solution for minutes. The nitrogen flow is then reduced to about one bubble per second. A reduction-oxidation catalyst system (redox system) is prepared by dissolving 1.71 parts 'ofammonium persulfate and 0.71 part of sodium meta-bisulfite, each in 100 parts of water. Portions of the catalyst solutions are added in 25-minute intervals over a period of 2. 5 hours. The-polymerization is continued for atotal period of 5-hours at C. The copolymer is collected on a Biichner funnel, Washed with 2000 parts of water and dried in an .oven at 70 C. for about 6 hours. Agood yield of dry, white copolymer of acrylonitrile and N-vinyl-N-('2-hydroxyethyl)imidazolium sulfate is obtained.

EXAMPLE 10 To a reaction vessel are .chargede parts of acrylonitrile, "2 "parts of N-vinyl-N-'(2-hydroxyethyl)imidazolium sulsulfate. The solution is heated on the steam'bath for 1 hour. The precipitate is collected on a Biichner funnel, 'Washedwi'th 500 parts of water and driedin an ovenat 70 C. for about 4 hours. A good yield ofdry, white copolymer of acrylonitrile and N-vinyl-N- Z-hydmxyethyl 'imidazolium sulfate is obtained.

EXAMPLE 11 by. dissolving 3.42 parts of ammonium persulfate and 1.42 "parts of sodium meta-bisulfite, each in 5100 parts of water.

The catalyst solutions are =added portion-wise to .themeacpart of potassium perparts of water, 0.30 part of a cationic "tionvessel at 25-minute intervals over a period tif iffi hours. The temperature is-maintained at 35 C. After a total period-of6 hours, the product is collected on a Biichner funnel, washed with 2,000 parts of demineralized Water and dried in an oven at C. for 5 hours. Ninetysix (96) parts of a dry, white tripolymer of acrylonitrile,

methyl acrylate and N-benzyl-N-vinylimidazolium bro- To a reaction vessel, equipped with a reflux condenser, are charged 9 parts ofmethyl acrylate, 1 part of N- methyl-N-vinylirriidazolium methylsulfate, 40 partsof water and Oil-part ofarnmonium persulfate. The solution is refluxed for 1 hour on a steam bath. The product is collected on a Biichner funnel, washed with 1.00 parts of Water and dried in an oven at 70 C. for 2. hours. .A good yield-of cream-colored, rubbery copolynrer o f-methyl acrylate and N-methyl-N-vinylimidazolium. methylsulfate is obtained.

EXAMPLE 14 ,polymer is added to a dye bath consisting-M1500. parts of an aqueous solution containing 0.2 part of sulfuric .acid, 1 part of sodium sulfate and 0.2 part of .Calcocid .Alizarine Blue SAPG (.Colorlndex No. 1054). 'The .dye bath.is boiled for 30 minutes, after which the .polymerizati on.product is filtered off and washed with hot water until the water is free of dye. The acrylonitrile copolymers of Examples. 8 to 11 inclusive, are dyedblue, whereas the homopolymeric .acrylonitrile of Example .6

and the acrylonitrile-methyl .acrylate copolymer of Example .7 failto absorb any dye.

The. advantage of-moditying-an facrylonitrilepolymerization product .by replacing .arpartteg from about 1% to about 25% or 30% or more, still more particularly from 2 or 3% to .15 or 20%) of the initial acrylonitrile .or other monomer with .a

quaternary imidazolium compound of the kind embraced by Formula Lthereby to obtain a copolymeric substance of improved dyeability, is therefore quite apparent.

EXAMPLE 15 holes microns in diameter, into a coagulatingbath comprising waterrmaintained at a temperature of about 0 C. The spun fiber in gel state is .continuously;passed .over a :pair of converging wash rolls while it is advancing in a helical path. The fiber is rinsed with water ton 21116111011810 remove excess thiocyanate... .flEh-emashed 1 11 fiber is stretched about 750% while passing through a bath of hot water maintained at a temperature of about 99.5 0., and then is taken up on a bobbin where it is .kept in a gelled state by applying a fine spray ot water ,while the fiber is being collected on the bobbin.

' Individual swatches of the gelled fiber are bleached ,by bringing to a boil in 3% aqueous hydrogen peroxide, followed by water washing, then bringing to a boil in 35 nitric acid, and again washing with water. After drying at room temperature, the bleached swatches are dyed in the same manner as described under Example 14. The "fibers are dyed to a deep shade of blue. In marked contrast, a fiber similarly prepared from homopolymeric 'acrylonitrile remains colorless when placed in the same dye bath for the same length of time.

It will be understood, of course, by those skilled in the art that my invention is not limited to the specific ingredients named in the above illustrative examples nor to 'the particular proportions and methods mentioned therein. Variations in starting materials, proportions, methods of preparation, etc., can obviously be made, as has been indicated in the portion of this specification prior to the examples.

Although many of the new copolymers of this invention, especially those containing a substantial proportion of acrylonitrile, are particularly useful in the formation of fibers or filaments which are more amenable to dyeing than homopolymeric acrylonitrile, these and the other copolymers of the invention also have numerous other applications in the plastics and coating arts. For instance, with or without a filler or other additive, they may be used as molding compositions (or as components of molding compositions) from which molded articles are produced by molding the compositions under heat and pressure, e.g., temperatures of the order of 130 C. or 140 C. to 200 C. and under pressures up to 10,000 pounds or more per square inch. Among the fillers that can be employed in the production of molded compositions are alpha-cellulose pulp, asbestos fibers, cotton flock, chopped cloth cuttings, glass fibers, wood flour, antimony oxide, titanium dioxide, sand, clay, mica dust, diatomaceous earth, etc.

The polymerizable compositions of my invention can be used in many difierent applications, for example as adhesives; in the treatment of paper or paper stock; in coating compositions; and for various other purposes. The polymer can be formed in situ after application of the monomer or mixture of monomers to the base material to be coated, impregnated or otherwise treated.

The unoriented and oriented fibers produced from my new fiber-forming copolymers are readily dyed, especially with an acid dye, while the fibe is in either a gel (e.g., aquagel) or a dry state. 7 Such fibers or other shaped articles produced from the copolymers (e.g., fabrics or other textile materials) also have, ingeneral, better anti- "static properties than polymers in which no quaternary imidazolium compound of the kind embraced by Formula I has been incorporated.

I claim:

1. A product comprising a fiber-formable copolymer obtained by polymerization of a mixture of copolymerizable ingredients including (1) acrylonitrile and (2). a quaternary imidazolium compound represented by the general formula 2. A product as m claim 1 wherein the quaternary 'following copolymerizable ingredients:

12 imidazolium compound of (2) is an N-benzy-N-vinylimidazolium salt.

3. A product comprising a fiber-formable, ternary polymer obtained by polymerization of a mixture of the fol- 'lowing copolymerizable ingredients: (1) acrylonitrile,

(2) a quaternary imidazolium compound represented by the general formula where R represents a radical of the class consisting-of alkyl, hydroxyalkyl and aralkyl radicals, and Y represents an anion, the compound of (2) constituting from about 71% to about 30% by weight of the total amount of (1) and (2), and (3) a compound which is different from the ingredients of (1) and (2), which is copolymerizable therewith and which contains a single CH =C grouping, the acrylonitrile of (l) constituting a preponderant proportion by weight of the total amount of the said copolymerizable ingredients, and the compound of (3) constituting the remainder.

4. A product as in claim 3 wherein the quaternary imidazolium compound of (2) is an N-benzyl-N-vinylimidazolium salt.

5. A product as in claim 3 wherein the compound of (3) is methyl acrylate.

6. A product comprising a fiber-formable, ternary polymer obtained by polymerization of a mixture of the (1) acrylonitrile, (2) an N-benzyl-N-vinylimidazolium salt, the compound of (2) constituting from about 1% to about 30% by weight of the total amount of (l) and (2), and (3) methyl acrylate, the acrylonitrile of (1) constituting a preponderant proportion by weight of the total amount of the said copolymerizable ingredients, and the compound of (3) constituting the remainder.

7. A spinning solution comprising the ternary polymer of claim 6 dissolved in a concentrated aqueous solution of sodium thiocynate.

8. A product comprising an oriented fiber comprised of a fiber-formable copolymer obtained by polymerization of a mixture of copolymerizable ingredients including (1) acrylonitrile and (2) a quaternary imidazolium compound represented by the general formula where R represents a radical of the class consisting 0 alkyl, hydroxyalkyl and aralkyl radicals, and Y"- represents an anion, the compound of (2) constituting from about 2% to about 20% by weight of the total amount resented by the general formula 1 where R represents a radical of the class consisting of alkyl, hydroxyalkyl and aralkyl radicals, and Y represents an anion, the compound of (2) constitutingfrom about 1% to about 30% by weight of the total amount of (1) and (2),

and recovering the resulting fiberformable copolymer.

References Cited in the file of this patent UNITED STATES PATENTS Price Aug. 5, 1952 14 Games Ian. 27, 1953 Ham Apr. 27, 1954 Coover et a1. Dec. 14, 1954 FOREIGN PATENTS Belgium Feb. 28, 1951 Belgium Mar. 31, 1952 Germany Aug. 21, 1952 OTHER REFERENCES Doolittle: The Technology of Solvents and Plasticizers (1954) page 261, published by John Wiley & Sons, Inc., New York. 4 v i 

1. A PRODUCT COMPRISING A FIBER-FORMULA COPOLYMER OBTAINED BY POLYMERIZATION OF A MIXTURE OF COPOLYMERIZABLE INGREDIENTS INCLUDING (1) ACRYLONITRILE AND (2) A QUATERNARY IMIDAZOLIUM COMPOUND REPRESENTED BY THE GENERAL FORMULA 